Short and sweet: Citrix Receiver in OpenSuSe Tumbleweed
I've just installed a fresh OpenSuSe Tumbleweed and just decided to write down as I install Citrix Receiver.
Download rpm from Citrix
At the time of writing the latest receiver rpm can be found Citrix website. Use SuSe full package, not the SuSe 11 SP3 package.
Install with zypper
zypper in ICAClient-suse-13.2.1.328635-0.x86_64.rpm
Check file association
Create a dummy ica launch file to check if it is already associated correctly
touch dummy.ica
There are multiple ways to do this.
I think in KDE you can search file associations from the start menu, look for Citrix and set .ica files to start with Citrix Receiver Engine.
In Gnome you can open file browser, click the right key on top of the dummy.ica and select properties - open with - Citrix Receiver Engine - Set as default.
Just in case you don't have the Citrix Receiver Engine listed you can always browse the application manually. It should be something like:
/opt/Citrix/ICAClient/wfica.sh
Check Firefox application association
In Firefox preferences - Applications see that Citrix ICA settings file is set to open with Citrix Receiver Engine.
Other considerations
It may be that you must install your organizations CA to access the Citrix gateway. Also you may have to set window size from full screen to a fixed size from the Citrix portal page (settings).
After this it just worked. Nice.